The present invention relates to a device for capturing a debris or blood clots in a blood vessel, and more particularly, it relates to a vascular filtering device for capturing and removing the debris or blood clots used in, e.g. percutaneous transluminal coronary angioplasty (PTCA) procedure.
In recent years, an inter-vascular treatment, such as PTCA, has been widely practiced for a treatment of stenosis in the artery. In the PTCA procedure, a catheter which is provided with a balloon at a distal end thereof is inserted into a blood vessel which has a stenosis, and the balloon is inflated to enlarge the stenosis. Also, after enlarging the stenosis, a stent may be provided for preventing re-stenosis.
In performing the PTCA procedure, however, it may cause other problems. Namely, debris or blood clots formed at the stenosis may be separated from the portion at the stenosis and migrate to other critical area, such as brain and pulmonary arteries, while the PTCA procedure is being performed.
In order to remove the debris or blood clots while the PTCA procedure is being performed, a device having a mesh or net may be disposed in the blood vessel, as proposed in U.S. Pat. No. 6,001,118. The net is inflated by various inflating means to catch emboli, but the net with the emboli may not be smoothly removed from the blood vessel after use.
The present invention has been made in view of the above problem, and an object of the invention is to provide a vascular filtering device for removing debris or blood clots in the blood vessel of a patient during an operation, such as balloon dilation procedure.
Another object of the invention is to provide a vascular filtering device as stated above, which can be easily delivered to a desired location in the blood vessel and removed therefrom after capturing the debris or blood clots.
A further object of the invention is to provide a vascular filtering device as stated above, which is formed easily and is used as a guide wire or tube for other procedure.
Further objects and advantages of the invention will be apparent from the following description of the invention.
A vascular filtering device of the invention is basically formed of a flexible shaft, an inflatable member attached to the shaft, and a filter member attached to the inflatable member and the shaft.
The flexible shaft has a side surface, a passageway extending inside the flexible shaft, and a side opening formed in the side wall at a distal end portion of the shaft to communicate with the passageway. A fluid may be supplied to the passageway from a proximal end of the shaft.
The inflatable member has a spiral or helical form and is attached to the distal end portion of the shaft to communicate with the passageway through the side opening of the shaft. The inflatable member has an outer side surface, and an inner side surface entirely fixed to the side wall of the shaft not to be separated therefrom.
The filter member has a distal end sealingly fixed to the distal end portion of the shaft and an open end at a side opposite to the distal end. The filter member extends along the flexible shaft to cover the distal end portion thereof and is fixed onto the outer side surface of the inflatable member along an entire length thereof. Thus, when the inflatable member is inflated by providing the liquid to the inflatable member through the passageway, the filter member is enlarged to allow a foreign substance, such as blood clots and debris, to enter into the filter member through the open end to capture the same. When the inflatable member is deflated by forcibly removing the liquid from the inflatable member, the filter member with the blood clots and debris is closed or disposed close to the side surface of the shaft. Thus, the filtering device can be easily removed from the blood vessel.
When the filtering device of the invention is used, the inflatable member is made in a fully deflated condition. The distal end portion of the shaft is inserted into a blood vessel from a portion used in a regular PTCA procedure, and the shaft is advanced to a desired location in the blood vessel passing through a portion to be treated later. Then, a liquid is supplied to the inflatable member through the passageway to thereby inflate the inflatable member. Accordingly, the proximal end of the filter member is opened and is held between an inner wall of the blood vessel and the inflatable member. Blood in the blood vessel flows along the inflatable member and passes through the filter member to remove a foreign substance, such as debris and blood clots.
In this condition, since the filter and the inflatable member do not block the blood flow in the blood vessel, a required PTCA procedure can be made smoothly. If debris or blood clots is formed by the PTCA procedure and flows in the blood vessel, the debris or blood clots can be captures by the filter member.
After the PTCA procedure is finished, the inflatable member is deflated by forcibly removing the liquid in the inflatable member. Then, the filter member with the debris blood clots is removed from the blood vessel together with the shaft.
In the invention, since the inflatable member is attached to both shaft and filter member along the entire inner and outer portions, when the inflatable member is inflated, the filter member can surely abuts against the inner wall of the blood vessel. When the inflatable member is forcibly deflated, the filter member is disposed close to the outer surface of the shaft with the debris or blood clots therein. Thus, the shaft with the inflatable member and the filter member can be easily removed from the blood vessel. The debris or blood clots is removed smoothly together with the filter member.
Preferably, the shaft of the filtering device is used as a guide shaft for allowing a vascular treatment device to be transferred in a blood vessel, resulting in that the guide shaft has the filtering member for capturing a foreign substance formed in the vascular treatment procedure.
In the invention, the filtering device may be transferred in the blood vessel through a guide wire. In this case, the shaft includes a partition wall in the passageway, and a port in the side wall near the partition wall. The partition wall divides the passageway into a first passageway extending from the proximal end portion of the shaft to the opening to communicate with the inflatable member, and a second passageway extending from the port to the distal end of the shaft to allow the guide wire to pass therethrough. The filtering device can be transferred to a desired location easily and rapidly through the guide wire already disposed in the blood vessel, as in the balloon catheter system.